i think youre overestimating how difficult it is to swap a tranny if guys can do it with their cars on jack stands then a shop with a lift shouldnt be racking up thousands in labor for a simple swap now if youre including a rebuild on the tranny thats going in then i could see the price going up but at that point he might as well have his current tranny rebuilt and skip the cost of buying a tranny that likely had similar issues that needs work